1. Field of the Invention
The present invention relates to a fishing reel, and more particularly to an improvement of a coupling structure for coupling a driving shaft with a handle in a fishing reel.
2. Description of the Prior Art
In general, a fishing reel, particularly a bait casting reel, has a handle coupled with and fixedly mounted on one end portion of the driving shaft by a nut, which includes a looseness prevention member for preventing looseness of a nut fastened at one end portion of the driving shaft. As examples, Japanese Unexamined Utility Model Publication Nos. Sho 55-108873 and Hei 3-74266 disclose looseness prevention members mounted and fixed on the respective handles in the form of protrusions protruded from the respective upper portions thereof the handles.
Since the looseness prevention members disclosed in the above publications are all constructed to be protruded from the respective upper portions of the handles, a problem has been raised against a possible wound of the user's fingers due to an inadvertent contact with the looseness prevention members in the course of adjusting the fishing reel with the handle. Moreover, slime such as fish, bait, dust, etc, is apt to adhere to the looseness prevention members, and the fishing reel might also be entangled or coiled around the looseness prevention members.
To overcome such problem posed by the conventional reel, EP 0 654 216 B1 (Mimura) teaches a looseness prevention member, the external surface of which is formed of a smooth surface extending to the center from the peripheral rim. This prior art was referred to in the present application.
An embodiment of the above-referenced European patent is illustrated in FIG. 1. Referring to FIG. 1, the looseness prevention member is coupled with a nut 40 for preventing looseness of the nut. The looseness prevention member comprises a cover 30 shaped in elliptical form so as to be inserted into a recess 12, which is shaped in the corresponding elliptical form at the center of an upper portion of a handle 10. The cover 30 has a recess 36 on the backside thereof for preventing looseness of the nut by being aligned on the clamped nut. The looseness prevention member can be fixed onto the handle by being coupled with a screw 42 in a hole 18 of the handle 10.
The looseness prevention member also has a curved surface forming a shape of being protruded slightly from the peripheral rim to the center thereof. Accordingly, if the looseness prevention member is fixed onto the handle, a smooth surface may be formed to be enhanced to the external curved surface of the handle. The smooth surface formed in that manner to be enhanced to the curved surface of the handle serves to eliminate the possible caught-up of the bait, user's finger or fishing reel by the looseness prevention member.
In the looseness prevention member disclosed in the Mimura patent described above, a recess is formed internal surface thereof so as to prevent looseness of the nut for fixing the handle onto the driving shaft. In other words, the recess of the looseness prevention member is in complementary shape with the nut so that the recess can be in close contact with the external peripheral surface of the nut.
The nut used for fixing the handle onto the driving shaft is normally a hexagon nut. Allowable tolerance is unavoidable in the course of manufacturing the fittings such as handle, driving shaft, etc. Therefore, the position of a nut clamped through rotation, i.e., the degree of orientation of a nut, cannot always be consistent when mounting the handle onto the driving shaft by means of the nut. As a result, the nut cannot be aligned in a consistent direction inside of the recess of the handle. In other words, even if a nut is applied to the same reel, the nut will have different orientation degrees in each reel. To the contrary, the recess formed on internal surface of the looseness prevention member has a consistent degree of orientation due to its elliptical shape. Thus, a precise engagement of the clamped nut with the recess of the looseness prevention member can rarely be expected even after completion of the coupling. To align the clamping nut to be precisely engaged with the recess formed on the looseness prevention member, it is necessary to additionally rotate the nut to a certain extent.
Enlarging the recess formed on the internal surface of the looseness prevention member to be slightly greater than the nut for the purpose of overcoming the above drawback is apt to pose another problem of loosening the nut inside of the recess.
Moreover, since the looseness prevention member is in elliptical shape and fixed onto the handle by means of a single screw, the surface opposed to the one fixed by the screw tends to be slightly protruded from the curved surface of the handle. Furthermore, foreign material such as slime, etc, might be adhered around the periphery of the head portion of the screw exposed to the external surface of the looseness prevention member.